Method of and machine for making knitted fabric



P 1962 G. LUMSDEN 3,052,108

METHOD OF AND MACHINE FOR MAKING KNITTED FABRIC 2 Sheets-Sheet 1 Filed May 3, 1961 ABCPEFG 2/ H II m U U [I I n n H il/ IJIIIIIJFJLIZI l I 1 f H INVENTOR.

4/ 22% we mm :J 74'' BY Sept. 4, 1962 G. LUMSDEN 3,052,103

METHOD OF AND MACHINE FOR MAKING KNITTED FABRIC Filed May 5, 1961 2 Sheets-Sheet 2 INVENTOR. 6egrye [mm 20 BY fla (QM ite This invention pertains to a novel method of making knitted fabric, and to a knitting machine for use in the practice of this method, in particular, to a straight-bed knitting machine of the kind wherein a frame supports two opposed needle beds, each provided with parallel needle grooves and with a hooked needle having an actuating butt in each groove, together with means for feeding yarn to the needle hooks and cam means for actuating the needles, and relates more especially to a machine designed to knit fabric which, unlike most customary knitted fabric, is elastically stretchable in the longitudinal direction to, at least, as great a degree as it is transversely.

Knitted fabric is extensively employed in garment manufacture, because of its ability to stretch elastically, thus permitting it to conform readily to the anatomy while, at the same time, affording freedom of motion. However, usual knitted fabric is capable of stretching to a much greater extent transversely of its width than in a direction at right angles thereto, and this is particularly true of ribbed fabric such as is produced upon a knitting machine employing two sets of needles. When the material is to be made elastic by the introduction of rubber elastic threads, it is usual to employ a ribbed fabric, because of the ease with which rubber threads may be laid into the fabric structure Without requiring that the rubber threads be drawn into stitch loops.

For use in knitting certain types of garment, it would be preferable (whether or not rubber elastic threads are to be incorporated) to employ a knitted fabric at least as stretchable in the direction of the needle wales as in a direction at right angels thereto. For example, in the manufacture of supporters for athletic use, knitted material is customarily employed in making the pouchlike portion, which is ordinarily only a few inches in width, so that to out such a piece from wide knitted goods would involve the formation of marginal hems which is not practical because of the cost as well as the increase in thickness at the margins. Thus, the fabric employed for the purpose is a selvage knit material which, as knitted, is of approximately the desired width of the garment part to be made. This obviously means that when using customary knitted goods, the needle wales extend lengthwise of the material, that is to say, parallel to the selvages and since such material is more stretchable transversely than longitudinally, the resultant garment, even though providing a reasonable degree of support when new, tends to become permanently stretched transversely as the result of use and of laundering and so, quickly loses its usefulness. An object of the present invention is to provide a novel method of making knitted material having selvages extending parallel to the needle wales and of a width suitable for use in making garment parts of the above type, but which is sufliciently stretchable and elastic longitudinally of the needle wales to possess the requisite ability to conform to a curved contour. A further object is to provide a novel method of making a fabric which is acceptable for the desired purpose, but which may be made at a cost substantially less, both as respects the amount of material employed and the speed of manufacture, than that of the usual fabric employed in such garments, and which, while retaining the desired functional characteristics, for a substantial period of time, is lighter in 3,052,108 Patented Sept. 4, 1962 weight, more porous, more permeable to air and moisture than the customary fabrics, and has a surface which is substantially devoid of ribs and thus smoother and softer to the touch than the materials ordinarily used. A further object is to provide improvements in a knitting machine of a well-known type whereby said method may be practiced readily and automatically and at high speed.

Heretofore in the manufacture of fabrics of this general type, it has been customary to employ a straightbed knitting machine wherein one only of the needle beds is movable longitudinally, relatively to the frame and so to actuate this machine as to produce what is known as a rack stitch fabric. In customary practice, after the formation of each course of stitches, the single movable needle bed is shifted relatively to the other needle bed a distance equal to the spacing between two adjacent needles, being moved first in one direction and then in the other by the same amount. This results in a fabric which may be somewhat smoother than the usual rib-knitted fabric, but has substantially the same stretch characteristics as the latter.

In accordance with the present invention, in the knitting of the novel material, both rows of needles are shifted longitudinally, but in opposite directions, and simultaneously, after the knitting of each course of stitches. Such shifting of the needle beds could be done as a manual operation, but is preferably carried out by mechanical means such as the machine herein disclosed.

The unexpected, surprising and highly useful result of this practice is that the knitted material, so produced, is substatnially less stretchable transversely of the needle Wales than the usual racked fabric, although highly stretchable and elastic longitudinally. The fabric is alike on both sides and is substantially devoid of anything resembling the customary longitudinally extending needle wales or ribs, such as those of ordinary one-andone ribbed fabric. Under magnification the fabric ap pears as a lacy structure with the legs of the stitch loops extending diagonally, those on one face sloping in one direction and those on the other face sloping in the opposite direction, the angle of slope being, for exam ple, 45. This fabric has but slight resemblance to usual racked fabric.

In a machine, such as that herein described, wherein the needles are actuated by cams, it is obvious that preparatory to racking the rows of needles the cams must have been moved out of operative engagement with all of the needle butts. In the customary straightbed machine, in which the cam carrier reciprocates, it is usual to provide two stitch cams spaced apart in each cam set, the rearmost of these stitch cams actuating the needles to draw stitch loops as the carrier moves in one direction in forming a course of stitches, the foremost of the two cams being idle so far as purposeful actuation of the needles is concerned during the formation of said course of stitches. It is obvious that, since both stitch cams must have disengaged the needles before the racking operation of the needle beds can take place, both cams must traverse the entire row of needles during the knitting of each successive course. In the making of ordinary knitted material, by reciprocating knitting, that is to say, wherein the cam carrier moves first in one direction and then in the other, the idle motion of the foremost cam of the set causes no difii culty, but it has been found that in knitting on a ma-' chine, such as above described, wherein the two needle beds are racked in opposite directions after the knitting of each course, the yarn is so tensioned that if the idle cam be permitted to remain in its normal position on the cam carrier, in performing the idle stroke, its action on the needles carrying the yarn laid during the next preceding course may cause yarn breakage. For this reason, the present invention contemplates the automatic setting of the forward stitch cam preparatory to its idle stroke, so that, as it passes the needles, it does not in any way actuate or prevent motion of the needles such as might result in breakage of yarn.

Apparatus wherein the above results are attainable is disclosed in the annexed drawings wherein:

FIG. 1 is a diagrammatic, transverse, vertical, front-trear section of a generally conventional straight-bed knitting machine of the Lamb type, but showing the two longitudinally movable needle beds of the present invention, each having a row of hooked needles mounted in grooves therein, and also showing portions of the carriage upon which the needle-actuating cams are mounted;

FIG. 2 is a diagrammatic, fragmentary plan view illustrating the two sets of needles as they are disposed when the two needle beds occupy one of their relative operative positions;

FIG. 3 is a view similar to FIG. 2, but showing the relative arrangement of the needles of the two rows when the needle beds have been racked to their other operative positions;

FIG. 4 is a fragmentary diagrammatic plan view of the machine of FIG. 1, to smaller scale, omitting all of the cam carrier except one end portion thereof and indicating means whereby the needle beds may be racked in opposite directions in accordance with the present invention;

FIG. 4a is a fragmentary elevation showing one of the needle-bed shifting cams;

FIG. 4b is a section on line 4b4b of FIG. 4 showing a portion of the cam carrier;

FIG. 5 is an elevation showing the cam carrier removed from the machine and so arranged that one side rail is in the vertical plane, with the means for shifting the stitch cams of one set mounted thereon, and in broken lines indicating the positions of the corresponding fixed stops relatively to the cam carrier, whereby the mechanism is caused to shift the cams prior to the knitting of each course of stitches;

FIG. 6 is a fragmentary view, to larger scale, showing the inner side of the rear rail of the cam carrier with one set of knitting cams in the position which they occupy as the cam carrier moves in the direction of the arrow Z, and in dotted lines showing the cams as they are positioned when the cam carrier moves in the opposite direction;

FIG. 7 is a view (to slightly smaller scale than FIG. 6) showing the cam-supporting plate which is secured to the rear rail of the cam carrier on which the cams are mounted, but with the cams removed, and illustrating the crank discs whereby the cams are shifted and the slots for guiding the cams in their movements;

FIG. 8 is a fragmentary elevation of the outside of the bar 22:: of the cam carrier, showing the bearings for the carn-actuating shafts of one set; and

FIG. 9 is a side elevation, to larger scale, showing one of the cam-actuating shafts removed from the cam carrier.

Referring to the drawings, FIG. 1 illustrates, in a diagrammatic way, a straight-bed knitting machine of the general type known as a Lamb machine, such machines being basically like that originally disclosed in the patent to Lamb, No. 39,934, dated September 15, 1863, such machines, as shown in FIG. 1, having, mounted upon a suitable frame 20, two needle beds 21 and 21a which are inclined upwardly toward each other and which are provided with grooves in their upper surfaces for the reception of the shanks of needles N and N here shown as latch needles having hooks at their upper ends and butts T engageab-le by the knitting cams, whereby the needles are moved in the formation of knitted stitches. The needle-actuating cams are mounted upon the under or inner sides of the spaced, parallel, longitudinally extending rails or bars 22a and 22b, respectively, of the cam carriage or carrier 22 which is moved by suitable means, customary in the art, longitudinally of the needle beds, so as to actuate the needles of both beds simultaneously in the formation of stitches. Since the means for moving the cam carriers is conventional and wellknown in the art, it is not herein illustrated.

As shown in FIG. 1, the machine is provided with tensioning rolls 23 and 23a which are driven at suitable speed by conventional means (not here shown) for drawing off the knitted web W as it is formed by the needles, the yarn being fed to the needles by the yarn guide Y, which is supported by and moved with the cam carrier 22.

In accordance with the invention, each of the needle beds 21 and 21a is mounted to slide longitudinally in suitable guideways such, for example, as are provided for guiding the single movable bed in prior rack-stitch machines.

As here diagrammatically illustrated, merely by way of example (FIG. 4), the needle bed 21 is provided with an extension L at one end carrying a cam follower element K (FIG. 4a) which engages a groove in a rotary cam I fixed on a shaft W, while the needle bed 21a is provided with a similar extension L' having a cam follower (not shown), like the element K, which engages a cam groove in a cam I fixed to the same shaft W. The cam I is provided with external gear teeth which mesh with a pinion H fixed to the main cam shaft k of the machine, the pinion H being half the diameter of the gear with which it meshes. Thus the cams I and I make a one-half turn for each rotation of the main shaft. The cam grooves are so contoured that as the shaft k turns, the needle beds 21 and 21a are simultaneously moved in opposite directions, each bed moving a distance equal to the space between adjacent needles, and each coming to rest before the cam carriage begins its advance movement and dwelling until the cam carrier has completed its stroke.

In FIGS. 2 and 3, relative positions of some of the needles in each of the beds 21 and 21a, respectively, is diagrammatically indicated by the characters A to G inclusive, and by the characters II to XIII inclusive.

Thus, as illustrated in FIGS. 2 and 3, and assuming that the cams have placed the two needle beds as shown in FIG. 2, so that the needle A, for example, is opposite the space between the needles II and III and that the needle beds dwell in this relative position while the cam carrier makes an operative stroke feeding the yarn to the needles of the two sets and thus knitting a course of stitches, the cams I and I, before the cam carrier starts its return journey, move the needle beds in the directions of the arrows M and N (FIG. 3), each a distance equal to the space between two needles, with the result that the needle C of the bed 21 now stands opposite the space between the needles II and III of the bed 21a. With the needle beds in this position, another course of stitches is knitted and then the needle beds are moved back by the cams I and I to the position of FIG. 2, whereupon the next course of stitches is knitted and then the needle beds are again moved to the position of FIG. 3 and so on.

It has heretofore been customary to make what is known as racked knitting by moving one needle bed one needle space, then knitting one course, and then racking it back before the next course, and so on, and it has also been suggested to make ornamental racked fabric in which one needle bed may be racked one step at a time several steps in the same direction and then back again, one step at a time. However, while the fabric made by so racking one of the needle beds is distinct in appearance from ordinary one-and-one rib fabric, such as would result from continued knitting on the needles as arranged in FIG. 2, course-after-course, any racked fabric as heretofore made exhibits longitudinally extending ribs and is substantially as extensible transversely of its width as ordinary ribbed fabric, and because of its distinct ribs has a surface which is rough to the touch. On the other hand, the fabric resultant from the manipulation of the needle beds, in accordance with the present invention is wholly distinct in appearance and feel from ordinary ribbed knitting, or from knitted fabric made by the customary racking operation. The fabric made by the apparatus herein disclosed is alike on both sides; its surface is substantially devoid of longitudinally extending ribs; the legs of the individual stitches are longer than those of ordinary one-and-one rib-knitted fabric and extend diagonally, for example at approximately 45 to the length of the fabric, and the long legs of the loops, at opposite sides of the fabric cross each other, giving a lacy appearance to the material. More important, from the standpoint of the present invention and the desired utility of the fabric, is the fact that the fabric is substantially as extensible longitudinally as it is transversely and, in fact, by suitably adjusting the tension imposed during knitting, it may be made to be substantially greater in longitudinal extensibility than transversely.

As a result of the simultaneous racking of the needle beds in opposite directions, the knitted loops are necessarily extended diagonally as will be appreciated from comparison of FIGS. 2 and 3, so that whereas a loop which extends from needle A to needle II, as the beds are shown in FIG. 2, is relatively short in length, a loop extending from needle A to needle II as the beds are shown in FIG. 3 is much longer. In experimental work in devising this material, it was found essential that the idle stitch cam be shifted so as to avoid putting undue strain on the yarn as the cam carrier travels along the row of needles. To accomplish this result, in accordance with the present invention, the stitch cams are mounted upon the cam carrier for movement toward and from operative position, with means for automatically shifting them just prior to the beginning of each knitting course. Thus, as shown in FIGS. 5 to 9 inclusive, the cam carrier 22, whose parallel bars or rails 22a and 22b respectively, are provided with like sets of knitting cams (only one set of which is here illustrated), are enlarged in width at their central portions 31 and 32 respectively, and upon the inner face of each of these enlarged portions there is fixed a cam-supporting plate 33 (FIG. 7) having pairs of parallel, inclined slots 34, 34 and 35, 35, respectively, for guiding the two stitch cams S and S respectively of the set, in moving toward and from operative position. This plate 33 is provided with two bearing openings in which rotary crank discs 36 (FIGS. 7 and 9) are arranged to turn, each disc having a crank pin 37 which is received in a horizontal slot 38 (FIG. 6) in the respective stitch cam S or S The cams are held, for movement, against the inner face of the plate 33 by headed studs 39 (FIG. 6), which slide in the slots 34 .and 3-5 of the plate 3-3. Each disc 36 is fixed to a shaft 40 (FIG. 9) which turns in a bearing sleeve 41 secured to the outer side of the enlargement 32 of the corresponding bar or rail 22a or 2211 respectively of the cam carriage 22, each shaft 40 having a pinion 42 located at the outer side of the respective cam carrier part, the pinions being secured to their shafts by nuts 43.

The pinions 42, at the front of the machine, for example, engage an elongate rack member 44 (FIG. 5), attached at its opposite ends to slidab-le rods 45 and 46 respectively, which slide in bearing members 47 and 48 fixed to the outer surface of the front rail 22b, it being .understood that a similar arrangement is provided upon the rear cam carrier rail 22a. Downwardly depending dogs 49 and 49a are fixed to the remote ends of the rods 45 and 46 respectively and are so arranged, relative to fixed stop members or abutments 5t) and 51, carried by the machine frame, that as the cam carrier moves in one direction (to the right as viewed in FIG. 5) the dog 49a will engage the stop 51 and thus move the rack 44 and so turn the pinions 42 as to rotate the discs 36, whereby the cranks 37 are so turned as to move the stitch cams 6 S and S in opposite directions, and when the cam carrier 22 moves to the left as viewed in FIG. 5, the dog 49 will contact the fixed stop 5% and thus move the rack in the other direction and so shift the cams S and S oppositely.

It will, of course, be understood that the cams I and I which shift the needle beds, are so timed by their actuating mechanism, that the needle beds are only shifted after the cam carrier 22 has reached the end of its stroke in one direction or the other and while the cams, mounted on the plate 33, are disengaged from the needle butts.

Let it be assumed, for example, the the cam carrier 22 has moved to the right from the position of FIG. 5 until the finger 49a has contacted the stop 51. Then the relative positions of the stitch cams S and S would be that shown in full lines in FIG. 6, and the cam carrier would then be ready to move in the direction of the arrow Z, the stitch cam S now being in the operative position while the stitch cam S is in the inoperative position. During this stroke the cam P will raise the needles to slip their old loops below their latches and to take a new yarn in their hooks, and the stitch cam S will then move the needles down to draw the new stitches and cast off the old loops. However, as the cam carrier moves in this direction, the butts of the needles which are carrying the yarn received during the next preceding course will not be drawn downwardly so far by the cam S that the yarn will be subjected to undue tension such as might result were the idle cam S in position to draw down the needle butts.

While herein one desirable means for shifting the stitch cams S and S has been illustrated by way of example, it is to be understood that other and equivalent means may be employed, and that any such means for attaining the desired result which falls within the scope of the appended claims, is to be regarded as within the purview of the invention, and likewise, as above noted, the means illustrated in FIG. 4, for shifting the needle beds alternatively in opposite directions, is merely suggestive. Obviously, each individual needle bed might be shifted by hand in accordance with such a sequence of operations as above described, or each individual bed might be shifted mechanically, for instance, by such means as is shown in the patent to Rist et al., No. 248,795, October 25, 1881, which provides for racking a single needle bed one needle space and then back again, but it will, of course, be understood that, in accordance with the present invention, whatever means might be employed for moving the beds would be arranged to move the respective beds oppositely while the cam carrier dwells at the end of each operative stroke.

I claim:

1. In a straight-bed knitting machine for knitting fabric which is at least as extensible longitudinally as transversely of its width, said machine being of the kind wherein a frame supports bearings for a drive shaft and for two opposed needle beds, each having parallel needle grooves, a hooked needle having an actuating butt in each groove, means for delivering yarn into the needle hooks, and knitting cams for actuating the needles to knit comprising a cam carrier and means for reciprocating it longitudinally of the needle beds, in combination, means guiding both needle beds to slide longitudinally, relatively to the frame and to each other, and racking means, actuated by the drive shaft, which is operative to move both beds simultaneously, but in opposite directions respectively, after each course of needle loops has been knitted and while the knitting cams are out of operative engagement with the needle butts.

2. The combination according to claim 1, wherein for moving the needle beds in opposite directions, there is provided cam means, moving in timed relation to the drive shaft of the machine, said cam means being so devised as to move each needle bed a distance equal to the spacing between adjacent needles prior to the beginning of the knitting of each successive course.

3. The combination according to claim 1, further characterized in that the racking means for moving the needle beds is operative to move each bed one needle space in one direction and one needle space in the opposite direction, alternately.

4. The combination according to claim 1, further characterized in that the knitting cams are so constructed and arranged as to avoid the application of breaking stress to the yarn as a result of the opposite racking motion of the needle beds.

5. The combination according to claim 1, wherein the cam carrier supports a pair of stitch cams for cooperation with the needles of each respective bed, the two stitch cams of each pair being movable from operative to inoperative position, and means operative automatically, as the cam carrier nears the end of its stroke in one direction, to shift to inoperative position the cam which will be the forward cam during the following stroke of the cam carrier and simultaneously to shift to operative position the stitch cam which was the forward cam during the stroke of the cam carrier just being completed.

6. The combination according to claim 1, further characterized in that the knitting cams include spaced stitchcams mounted upon the cam carrier, which are operative, respectively, by engagement with the needle butts, to draw stitches as the carriage moves alternately in opposite directions, means operative automatically so to position that stitch cam which is foremost in a given direction of movement of the carriage, that it cannot actuate the needles to impart injurious tension to the yarn.

7. The combination according to claim 6, wherein, for positioning the forward stitch cam, so that it will not eliectively move the needles, each stitch cam is movably mounted on the am carrier, means, comprising a pinion, for moving each respective cam, and a rack bar engaging both pinions and Which, by relative motion of the rack bar and cam carrier, rotates the pinions thereby to move both cams simultaneously.

8. The combination according to claim 7, wherein for moving the rack bar there is provided a dog fixed relatively to the rack bar and a fixed stop engageable by said dog as the cam carrier nears the end of its stroke in one direction.

9. The combination according to claim 7, wherein for moving the rack bar there are provided dogs fixed relati vely to the rack bar and located near opposite ends, respectively, of the cam carrier, and spaced stops engageable by the respective dogs as the cam carrier nears the end of its stroke in opposite directions.

10. In combination a straight-bed knitting machine having two needle beds, each furnished with knitting needles, means supporting and guiding both needle beds to slide longitudinally, a cam carrier movable longitudinally of said beds, a pair of stitch cams cooperable with the needles in each respective bed, the cams of each pair being movably mounted upon the cam carrier, means operative simultaneously to move the needle beds in opposite directions while the stitch cams are disengaged from the needles, and means operative to shift the stitch cams, after the formation of each knitted course, so that the stitch cam, which will be idle during the formation of the next course, is disposed in inoperative position.

11. The combination according to claim 10, wherein the cam carrier comprises an elongate bar overlying each respective needle bed, each bar having a cam-supporting plate at its inner side, each respective plate having a pair of parallel, inclined slots, and each stitch cam having studs which slide in the slots of a pair thereby to guide each cam for movement from an operative to an inoperative position relatively to the needles, actuating means mounted upon each respective bar of the cam carrier for moving the cams of the corresponding pair in opposite directions, and means for operating said actuating means, as the cam carrier nears the end of its stroke, in opposite directions respectively.

12. The combination according to claim 10, wherein the actuating means for shifting the stitch cams of a pair from operative to inoperative position, and vice versa, comprises a rotary crank having a pin engaging a horizontal slot in each stitch cam of a pair, a rotary shaft to which each crank is fixed, each such shaft extending to the exterior of the corresponding bar of the cam carrier, a pinion fixed to each shaft, an elongate rack engaging both pinions of a pair, and means operative to move the rack longitudinally and thereby simultaneously to turn the two pinions when the cam carrier nears the end of its stroke in each direction respectively, the two cranks being so arranged that, in turning in the same direction, they move the stitch cams of a pair in opposite directions.

13. That method of knitting a fabric which is alike on both sides and which is at least as stretchable longitudinally as it is transversely of its width which comprises as steps: providing two parallel rows of hooked knitting needles, the needles being uniformly spaced apart to the same amount in both rows and with the needles in one row initially disposed approximately opposite the midpoint between adjacent needles of the opposite row, laying a yarn into the hooks of all of the needles of both rows, relatively moving the yarn and the needles so as to form a loop of yarn upon each needle, bodily moving each row of needles longitudinally a distance equal to one needle space, the two rows being moved oppositely, again laying the yarn into the hooks of all of the needles, and so relatively moving the yarn and the needles as to cast off the previous loops over the newly formed loops of yarn upon the needles so as to form stitches, then moving the two rows of needles back to their original positions, and repeating the above steps cycle-after-cycle in the formation of knitted material.

14. The method according to claim 13, wherein the needles are latch needles and each is movable longitudina'lly in the taking of the yarn in its hook and casting off of a stitch, and, in the formation of each row of stitches, progressively actuating the needles of each row, beginning at one end of the row and advancing toward the opposite end, to form a course of stitches and, in so actuating the needles, avoiding the downdrawing of any needle, prior to its elevation to receive a new yarn in its hook, until said course has been completed thereby to avoid the application of breaking stress to the yarn.

References Cited in the file of this patent UNITED STATES PATENTS 232,834 Marshall Oct. 5, 1880 244,079 Rist July 12, 1881 265,359 Angst Oct. 3, 1882 670,159 Millholand et a1. Mar. 19, 1901 838,065 Whitcomb Dec. 11, 1906 1,072,856 Kellner et al. Sept. 9, 1913 

